System for starting synchronous telegraph motors



March 17, 1942. POT' 2,276,738

SYSTEM FOR STARTING SYNCHRONOUS TELEGRAPH MOTORS Filed Sept. 2, 1959 F IG. 5 VENTOR RNEY.

Patented Mar. 17, 1942 SYSTEM FOR STAR-TING SYNCHRONOUS TELEGRAPH MOTORS Louis M. Potts, Evanston, Ill., assignor to Teletype Corporation, Chicago, 111., a corporation of Delaware Application September 2, 1939, Serial No. 293,160

7 Claims.

The present invention pertains to telegraph systems and particularly to combination telegraph and telephone systems.

An object of the invention is the provision of a system wherein synchronism between a driving motor of a substation telegraph apparatus and a driving motor of the central office telegraph equipment is maintained by transmitting alternating currents from the central office over a communication line, independently of telegraph communication signals concurrently transmitted over the line.

A further object of the invention is to start a telegraph substation synchronous motor by direct current supplied from the central office and thereafter to maintain such motor in synchronous rotation by alternating currents.

A further object of the invention is to use line conductors for telegraph signals and for motor power concurrently.

A feature of the invention is to provide on one telephone line two independent circuits for. telegraph operation, the said two circuits being either conductively independent or conductively dependent but operatively independent, then to use one of said circuits for maintaining a telegraph motor in synchronous rotation with a central office motor, and to use the other of said circuits for telegraph communication, utilizing further a portion of the telegraph communication circuit for a short period for starting the telegraph motor at the substation.

A further feature of the invention is the provisionof manually operable means at the central office by which an operator at the central ofi'ice, having seized a line by switching means, may change the circuit conditions of the seized line to motor starting condition and subsequently to telegraph transmission condition.

To attain the noted features and objects, a telephone line having usual substation and cen tral ofiice telephone equipment is provided fur ther with substation telegraph equipment including a receiving recorder, a relay responsive to control from the central ofiice and a motor which may be driven in continuous rotation by alternating current and which may be started by direct current.

For controlling the substation equipment, according to one embodiment of the invention, central ofiice apparatus cooperates with substation apparatus to form a motor power circuit over one line conductor and a telegraph signaling circuit over another line conductor. In absence of energizing conditions for the noted substation rent over the signaling conductor, a source of alternating current may be connected to the motor power circuit, energizing the motor to run continuously and energizing the substation relay to operate its armature, thus forming the telegraph signaling circuit through contacts of the energized relay and including the receiving recorder therein.

When the combination telephone and telegraphline is idle, it may be seized for use for telephone service or for telegraph service, but while the line is in use for telephone service, ad,- ditional contacts on the telephone hook switch remove the telegraph equipment from association with the line conductors, and while the line is in use for telegraph service, the telephone equipment of the substation is disabled by con-, tacts in the substation relay.

The substation telegraph motor when thus started runs in synchronism with a continuously operating central office telegraph m'otor'which is driven from the same source of alternating power current. i I

In modified structures embodying the invention, the motor power path may be a grounded phantom circuit formed from the two sides of a physical metallic telegraph signaling circuit, an axially shiftable motor armature may be provided with switching contacts to effect the functions of the substation relay, or a polar relay in the telegraph signaling circuit may replace the noted alternating current substation relay, current in one polar sense being supplied at the central office to control the polar relay to form a motor starting circuit at the substation and current in the other polar sense being supplied at the central office to control the polar relay to forma telegraph signaling circuit including the recording receiver at the substation.

A more complete understanding of the invention will be obtained from the following description, taken in connection with the accompanying drawing,.in which like numerals indicate like parts and in which,

Fig. 1 illustrates a telephone substation apparatus and central oflice controlling apparatus providing conductively separate circuits for motor .power and for telegraph signaling with ground return; I

Fig. 2 illustrates a system embodying a phantom circuit for motor power and a metallic circuit for telegraph signaling;

Fig. 3 illustrates a modification of the system of Fig. 1 with polar control for forming a motor starting circuit;

Fig. 4 illustrates a modification of the system of Fig. 2 in which the motor armature effects the functions of the alternating current relay of Fig. 2;

Fig. 5 shows a modification appplicable to any of the illustrated systems should it be desired to transmit telegraph signals of alternating current or of resonant nature; and

Fig. 6 illustrates switching equipment of the telephone system for interconnecting telephone lines for telephonic communication.

In general, all telephone lines served by jacks as I, 2, 3, 4 in a telephone exchange may be interconnected for telephone communication by connective links as 5, Fig. 6. exchange, any substation telephoneset, as 6, i, 8 and 9, may have added thereto a telegraph set which may be connected to the telephone line conductors through contacts in the telephone hook switch which may be closed when the telephone is not in use and when the telephone receiver is on the hook. Thus, telephone operators at the central office may call the telephone set into operation by ringing its bridging bell as it or telegraph operators at the central oflice may call the telegraph set into operation by starting its driving motor Telegraph equipment at the central office is provided in the form of a plug as |2 which may b inserted in any'telephone jack as to engage a line, each such plug being provided with a manual key as l3 for setting up motor starting conditions for the substation motor II, and each operator being provided with a transmitter M of design to control a substation recorder 2|, a home recorder i5, and a continuously rotating driving motor l6.

According to the system illustrated in Fig. l, the substation has a telegraph recorder 2| driven by a motor II, the motor comprising field magnets N, S, a synchronous winding or alternating current winding 22 connected to feed rings 23, and a divided or direct current starting winding 24 connected to segments of commutator 25. The synchronous winding 22 is connected from ground through condenser 26, winding of alternating current relay 2'! and hook switch contacts 28 to the upper conductor of the line 25, while the starting winding 24 is connected from ground through back contacts of relay 21 and hook switch contact 28 to the lower conductor of the line 29. The telegraph recorder 2|, symbolized by its selector magnet, is connected from ground to front contacts of relay 27. Contacts in relay 2! shunt the contacts 28 when the relay 21 is operated and a further contact 3| in relay 21 opens the circuits of the telephone bell l0 and of the induction coil winding 30'when the relay 2? is operated.

At the central ofiice, the tip of plug I2 is connected through normally closed contacts of key l3 to alternating current generator and the ring of plug |2 is connected through recorder magnet l5, transmitter contacts I4 and battery 36 to ground. The ring of plug i2 is further connected to a normally open contact of key l3, a cooperating contact being connected to battery 31. Battery 38 is connected to the body member of plug |2 to supply current through jack I for energizing and operating the cutoff relay 35 to disconnect the signaling equipments 48 and 4|.

In such a telephone Motor I6 is driven continuously by generator 35 over an obvious circuit.

In operation, according to the system illustrated in Fig. 1, the operator at the telegraph set comprising transmitter l4 and recorder l5 inserts plug l2 in jack and operates key l3 manually. Battery 38 operates relay 59 and battery 37 starts motor and drives it up to synchronous speed or higher by current over a circuit including battery 31, closed contacts of operated key l3, ring of plug l2, lower conductor of line 29, upper hook switch contacts 28, back contacts of deenergized relay 21, commutator 25 and starting winding 24 to ground. Upon release of key l3, a normal motor driving circuit is formed including generator 35, contacts of key l3 now normal, tip of plug l2, upper conductor of line 29, lower hook switch contacts 28, Winding of relay 2T, condenser 26, feed rings 23 and driving winding 22 of motor II to ground. Relay 2! attracts its armature and connects recorder magnets 2| to form the definitive telegraph signaling circuit including battery 36, transmitter I l, recorder I5, plug 12, jack line 29, hook switch contacts 28, front contacts of operated relay 2? and recorder magnet 2| to ground. The telephone set 6 now is disabled by contact -3| of relay 2! which opens the circuit of induction 'coil winding 36 and of hell II], at the same time removing the bell H) from recorder magnet 2| as a shunt. Substation recorder 2| now is responsive to 'operators transmitter l4 and a home record at the central ofiice is produced by recorder |5. Should it be desired that telegraph transmission be effected by alter nating current, a generator as 42, Fig.5, maybe associated with transmitter i in place of battery 36.

In Fig. 2 there is shown a modification of the structure of Fig. 1 for metallic loop telegraph signaling. A driving circuit for substation motor 5! is formed when plug 52 is inserted in jack 2 and includes generator 53, phantoming diiierem tial inductances 54 in parallel, inner contacts in parallel in key 55, plug 52, jack 2, conductors in parallel in line 55, hook switch contacts 51 in parallel, phantoming condensers 58in parallel, wind ing of alternating current relay 59, and synchronous driving winding 60 of motor 5| to ground. Current in the described circuit energizes relay 59 to form a. metallic loop telegraph signaling circuit including battery 6 transmitter contacts 63, home recorder magnet 62, winding 44 of an inductive bridging coil 44'45, upper contact and switching spring of key '55, tip members of plug 52 and 'jack 2, upper conductor of line 56, upper pair of hook switch contacts 57, substation recorder magnets 64, contacts of operated relay 59, lower pair of hook switch contacts-51, lower conductor of line 55,- -ring members of jack 2 and plug 52, lower switch spring and inner contact of key 55, and winding of bridging coil 44 45, to battery 6|. Contacts '32 in relay 59 disable the telephone set I by opening the circuit of the induction coil winding 3 1 and bell 53, at the same time removing the bell 3 3 from the recorder magnet 64 as a shunt. Operation of key eiiects a starting circuit for motor5| by opening the described driving circuit to deenergize relay 59. A starting circuit then is formed comprising a metallic loop from battery 65 and ground through both of the outer contacts of operated key 55, plug 52, jack '2, line 56, contacts 51, 'back contacts of deenergized relay'59, and starting winding '66 of motor 5|. u I

Operation of the structure illustrated in Fig. 2

is similar to that of Fig. 1, in that the operator inserts plug 52 and operates key 55 during a time period sufiicient to permit motor to reach operating speed, when by release of key 55 the described starting circuit is interrupted and the described driving circuit is formed, resultantly energizing the relay 59 to complete the described metallic loop telegraph signaling circuit.

Fig. 3 illustrates a structure in which one conductor of the telephone line 19 is utilized to form a grounded driving circuit for substation motor H and the other conductor of line is utilized to form a grounded telegraph signaling circuit, a substation motor control relay 12 being controlled in polar manner by reversal of current in the telegraph signaling conductor instead of by current in the driving circuit as shown in relay 21, Fig. 1 and relay 59, Fig. 2.

In operation of the structure of Fig. 3, beginning by insertion of switching plug 13 in jack 3,

a definitive driving circuit is formed including generator 14, ring members of plug 13 and jack 3, lower conductor of lin 10 upper hook switch contacts 15, driving windin 16 of substation motor 1|, condenser 11 and ground. By operation of manual key 18, a starting battery 19 having its negative pole grounded, is connected to complete a starting circuit including polar battery 19, contact of key 18, tip members of plug 13 and jack 3, upper conductor of line 10, lower contacts 15, winding of polar relay 12, contacts of relay 12, starting winding 80 of motor 1| and ground. Polar sense of current through winding of relay 12 is such as to retain the armature in the position illustrated. Release of key 18 leaves motor 1I operating under power from generator 14. Reclosure of the inner contact of key 18 permits a current from battery 82, having its positive pole grounded, through home recorded magnet 83, transmitter contacts 8I, contacts of key 18, tip members of plug 13 and jack 3, upper conductor of line 10, lower contacts 15, winding of relay 12 and to contacts of relay 12, whence an initial portion of the current flows through starting winding 89 to ground, the relay 12 immediately responding to the reversal of polarity of current to reverse the relay armature, after which the circuit is extended from contacts of relay 12 through substation recorder magnet 84 to earth. Reversal of contacts 88 of relay 12 opens the circuit of the telephone bell 86 and induction coil winding 81. Condenser 85 forms a shunt around the winding of relay 12 for telegraph signal currents.

In the structure illustrated in Fig. 4, the armature of a substation motor 90 is utilized to efiect functions of an electromagnetic relay, by providing a mechanical spring 9| pressing against the end of the armature shaft 92 of the motor and capable of moving the shaft axially when no current flows in any winding of the armature. Contact springs 93 are controlled by spring 9| and are open when no current flows in any armature winding. Contact springs 89 are controlled by spring 9| and are closed when no current flows in the armature.

Operation of the structure illustrated in Fig. 4 is begun by inserting plug 94 in jack 4, completing a phantom driving circuit for motor 90 including generator 95, differential phantoming inductances 96, inner contacts and switching springs of manual key 91, plug 94, jack 4, both conductors of line 98, hook switch contacts 99,

' phantoming condensers I00, driving winding IM and ground. Motor 90 does not start, but by magnetic effect of current in the described circuit the armature windings cooperate with the pole faces of the motor to move the armature shaft axially against tensionof spring 9I and thus cause contacts 93 to close together. Operation of manual key 91 now interrupts the described current in the driving circuitand replaces the magnetic effect in the motor to hold contacts 93 closed by supplying a motor starting current in a metallic loop starting circuit which includes battery I02 and ground, both of the outer contacts, and both switching springs of key 91, plug 94, jack 4, both conductors of line 98, hook switch contacts 99, starting winding I03, and substation recorder magnets I04. Upon release of manual key 91, the described driving circuit is restored and motor now continues in rotation, also holding closed the contacts 93 and holding open the contacts 89. Telegraph signaling is over a metallic loop circuit including battery I05, transmitter contacts I01, recorder magnets I06, winding I01 of an inductive bridging coil I01I08, upper inner contact and upper switching spring of key 91., tip members of plu 94 and jack 4, upper conductor of line 98, upper pair of hook switch contacts 99, starting winding I03, closed contacts 93, recorder magnet I04, lower pair of contacts 99, lower conductor of line 98, ring members of jack 4 and plug 94, lower switching spring and lower inner contact of key 91 and winding I88 of coil I01I08 to battery I05. The starting winding is shunted by condenser I08. Contacts 99 hold open the telegraph circuits when the telephone is in use and contacts 89 hold open the circuits of induction coil Winding I09 and bell H0 when the telegraph is in use.

The invention has been illustrated herein by embodiment in specific structures, but it is to be considered as accurately described only by the spirit and scope of the appended claims.

What is claimed is:

1. In a signaling system, central oifice apparatus, telephone and telegraph substation apparatus, a line connecting said substation apparatus and said central ofiice apparatus, a motor included in said substation apparatus, a starting winding in said motor, a driving winding in said motor, a startng circuit including said starting winding, a driving circuit including said driving winding, a manual key included in said central oflice apparatus having key contacts in said starting circuit and in said driving circuit connected to close said circuits alternatively, and means effective through the operation of said key to render said telegraph apparatus effective and said telephone apparatus ineffective.

2. The comb-inatin claimed in claim 1, in which said starting circuit is a metallic circuit and in which said driving circuit is a phantom circuit.

3. In a combined telephone and telegraph system, a telephone line, a telephone set connected to said line, a telegraph set including a driving motor connected to said line, a driving circuit for said motor, a starting circuit for said motor, a relay responsive to motor-driving current having a winding included in said driving circuit and having contacts included in'said starting circuit, said contacts connected to open said starting circuit in response to driving current in said winding in said driving circuit, and a manually operable key having key contacts in said driving circuit and further key contacts in said starting circuit, said key contacts and said further key contacts being alternatively closable by said key to close alternatively said driving circuit or said starting circuit.

4. The combination claimed in claim 3, in which said starting circuit is a metallic circuit and in which said driving circuit is a phantom circuit.

5. In a telegraph system, a substation, telegraph apparatus including a driving motor and a control magnet at the substation, a central station, a circuit connecting the substation to the central station, means operated by one polarity of current transmitted from the central station over the circuit to connect the circuit to the motor and operable by the other polarity of current to connect the circuit to the control magnet.

6. In a telegraph system, a telegraph circuit, telegraph apparatus including a motor and a control magnet at one end of the circuit, telegraph apparatus at the other end of the circuit, means to apply motor starting current to the circuit at the last mentioned end of the circuit and to disconnect the motor starting current and apply signaling current to the circuit, means at the first end responsive to said current to control the connection of the motor to the circuit, and means included in the second mentioned means to disconnect the motor and connect the circuit to the control magnet.

7. In a telegraph system, a telegraph circuit, telegraph apparatus including a motor and a control magnet at one end of the circuit, telegraph apparatus at the other end of the circuit, means to apply motor starting current to the circuit at the last mentioned end of the circuit and to dis- .rent to the motor thereafter to maintain its speed.

LOUIS M. POTTS 

